Apparatus which proportion, mix and dispense liquids or solids suspended in liquids have long presented a problem to industries which require the use of such mixtures which are abrasive or otherwise present difficulties in handling. Further apparatus of this type employing pumps and the like are relatively expensive and many times are less than satisfactory relative to the accuracy desired.
For example, a graphite suspension mixed with a large proportion of water is useful in conditioning tools and dies in the forging industry. Such a suspension, however, is very abrasive when in conventional pumps or cylinder piston arrangements. Breakdowns are so common as to make such apparatus very unsatisfactory.
Further, prior dispensing and proportioning apparatus for large scale industrial applications did not possess the desired level of accuracy without incurring a disproportionate cost and then reliability was not always as consistent as desired particularly with difficulty to handle liquids.
Therefore a long felt need has existed for a relatively simple and inexpensive liquid proportioning device which has the capability to handle highly abrasive substances in a highly accurate and reliable manner.